Metal cutting tools such as turning tools, drills and saws have used carbide inserts to improve the life of the cutting edge, and with certain types turning, sawing and drilling operations cutting edges formed of polycrystalline diamond compositions have been used which provide even greater life than carbide tools. Examples of polycrystalline diamond cutting tools are shown in U.S. Pat. Nos. 4,605,343; 4,702,649 and 4,714,385.
While tools using polycrystalline diamond cutting edges have been used primarily with turning tools the advantages of this type of cutting edge have not previously been incorporated into an end mill.
It is an object of the invention to provide an end mill of such construction as to utilize the advantages of polycrystalline diamond cutting edges.
Another object of the invention is to provide an end mill having polycrystalline diamond cutting edges wherein the mill is readily usable with conventional milling machines, and may be employed by milling machine operators without requiring special skills or knowledge.
A further object of the invention is to provide an end mill having polycrystalline diamond cutting edges wherein the polycrystalline diamond edges are defined upon an insert which may be readily installed upon, or removed from, an end mill body for maintenance, sharpening, repair, and the like.
In the practice of the invention a substantially cylindrical end mill body having an end which is clamped within the machine tool spindle includes a recess defined in the other end region of the body. A flat pad surface is defined in the recess receiving a cutting insert having a sharp lateral cutting edge, and a sharp end cutting edge. A layer of polycrystalline diamond material is embedded into the insert defining the effective cutting edges thereof wherein the insert is capable of both side mill and end milling operations.
An obliquely disposed threaded hole is defined in the end mill body which receives a screw extending through a hole defined in the insert for attaching the insert upon the end mill body. The recess includes flat shoulders lying in planes specifically related to the geometry of the body engageable by insert edges wherein the insert will be accurately and firmly positioned with respect to the body.